JPH0464535A - Sheet feeding device - Google Patents

Abstract

PURPOSE:To facilitate refill of sheets by driving a feed roller through a clutch, and allowing the intermediate plate of a tray to approach or separate to/from the feed roller through the action of a train of cams furnished on the shaft of feed roller. CONSTITUTION:The drive force of a drive shaft 16 is transmitted to a feed roller 15 through an electromagnetic spring clutch 39. Each sheet P1 on a sheet accommodation tray 12 is fed with rotation of the feed roller 15. When a sensor 42 senses passage of the sheet P1 fed, a computer gives the remaining current feed time command to an electric circuit 40 of the clutch 39, and one cycle of sheet feeding is completed. A train of cams 45 are mounted on the drive shaft 16, and an intermediate plate 30 in the fore half of the tray 12 is energized in the direction of approaching the feed roller 15 with an eccentric cam 45a with half a turn of the feed roller 15, and now it is possible to feed sheet. Another half a turn will cause separating, and repetitions provide possibility of continuous sheet feeding. Refill of sheet to the tray 12 can be facilitated by stopping the operation in this separated state.

Description

DETAILED DESCRIPTION OF THE INVENTION (A) Field of Industrial Application The present invention relates to a sheet material feeding device that feeds sheet materials one by one to a main unit that performs image formation, such as a laser beam printer or a copying machine.

(B) Prior Art FIG. 9 shows an example of a conventional apparatus main body and sheet material feeding apparatus such as a laser beam printer for forming images.

In the figure, a laser beam printer (apparatus main body) includes a main body frame 2 and a printer front plate 5 whose base is pivotally connected to the main body frame 2 by a hinge shaft 3 and which can be opened and closed. A process cartridge 6 having a photosensitive drum 7, a developing device 9, etc. is removably disposed within the main body frame 2, and the laser beam L output from the laser beam scanner 10 is irradiated onto the photosensitive drum 7 and An image is formed and developed by a developing device 9 to form a toner image.

A paper feed tray 12 storing sheet material P is detachably attached to the printer front plate 5, and the sheets (PI) are separated one by one by a paper feed roller 81 and a separation pad 82. The sheet material P fed from the registration roller pair 17 at a predetermined timing has a toner image transferred thereto on the photosensitive drum 7, and is then fed to the pair of registration rollers 17 on the downstream side. The image is fixed and further discharged onto a paper discharge tray 26 by a group of discharge rollers 25 .

As shown in FIG.
is urged upward by. FIGS. 11 and 12 show a mechanism for applying and releasing pressure on the sheet material P1 to the paper feed roller 81. FIG.

In the figure, the drive link 93 receives a driving force from the main body, and this driving force is transmitted to the paper feed roller 8 through the control ring 90.
1 and is transmitted to a drive shaft 80 that is integrated with 1.

Either the drive shaft 80 or the solenoid 9 as shown in FIG.
In the state in which the paper feed roller 81 is locked by the first claw 91a, the driving force of the drive link 93 is not transmitted to the drive shaft 80, and the paper feed roller 81 is in a stopped state. A support arm 87 integral with the middle plate 83 is swingable around a support shaft 86, and a roller 87a provided at its free end is a large diameter pressurizing cam 89 fixed to the drive shaft 80. It is in pressure contact with the part.

When the upper solenoid 91 is activated by the electric circuit 92, the claw 9
1a comes off from the control ring 90, which causes the drive ring 93 to
The driving force is transmitted to the drive shaft 80. When the feed roller 81 and pressure cam 89 integrated with the drive shaft 80 rotate in the direction of the arrow, the roller 87a falls into the small diameter portion of the pressure cam 89 and rises as shown in FIG. The sheet material P on 83 is pressurized by the paper feed roller 81 and is fed by the paper feed roller 81 .

When the protrusion of the drive link 93 rotates once and is again locked by the claw 91a, the rotation of the paper feed roller 81 is stopped, and the support arm 87 returns to the position shown in FIG. 11, thereby feeding the sheet. Material P.

Pressure between the paper feed roller 81 and the paper feed roller 81 is released.

(c) Issues to be Solved by the Invention However, the above-mentioned conventional sheet material feeding device has the following problems.

(1) Between the outer diameter of the paper feed roller 81 and the paper bus length I21 from the paper feed roller 81 to the registration roller pair 17, Dπ
>P, >Dπ-a, (a = 0 to 15 sheets, D: conveyance roller diameter) physical restrictions occur.

(2) The middle plate 83 must be raised and lowered via the support arm 87 by one rotation of the pressure cam 89 for each paper feed.

(3) Due to the structure of raising the support arm 87, the pressure cam 8
The depressed part 89a of 9 has a steep slope, and the middle plate 83
An impact noise is generated between the paper feed roller 81 and the paper feed roller 81.

(4) Since the drive shaft 80 and the paper feed roller 81 are fixed, the pack tension against the pair of registration rollers 17 is large.

(5) From the previous sections (1), (2), and (3), there are certain restrictions on the number of sheets that can be loaded.

Therefore, the present invention provides a sheet material feeder that eliminates the need to control the intermediate plate each time the sheet material is fed and allows the rotation speed of the feeding means to be freely set according to the paper path. The purpose is to provide a transmission device.

(d) Means for Solving the Problems The present invention has been made in view of the above circumstances, and for example, as shown with reference to FIGS. 1 and 2, sheet material (P
The sheet material (Pl) stored in the sheet material storage section (12) is sent to the main unit (1) which receives the feeding of the sheet material (P, ) and performs a predetermined image forming process on the sheet material (P,). In a sheet material feeding device that feeds sheets one by one, the sheet material feeding means (15) feeds the sheet material (P I ) in the sheet material storage section (12), and the sheet material feeding means (15) It is characterized by having a drive transmission means (39) for driving.

Further, the sheet material storage section (12) is arranged in the feeding means (1).
5) and the drive transmission means (39) together with the sheet material (P
1) is provided with a sheet material storage section drive means (A) for pressurizing and releasing the sheet material storage section (A) from the feeding means (15).

(E) Function Based on the above structure, the sheet material feeding means (15) is rotated by the operation of the driving means (39), and the sheet material storing section (12) is rotated.
) The sheet material (Pl) inside is fed. Further, the sheet material (P,) in the sheet material storage section (12) is moved by the sheet material feeding means (1) by the operation of the sheet material storage section driving means (A).
5), the pressure is applied and released, and the feeding of the sheet material (P,) and the replacement and replenishment of the sheet material (P,) are easily performed.

Note that the above-mentioned symbols in parentheses are for reference to the drawings and do not limit the structure of the present invention in any way.

(f) Example An embodiment of the present invention will be described below with reference to the drawings.

FIG. 1 shows a longitudinal cross-sectional side view of a laser beam printer (image forming apparatus) 1 to which a first embodiment of the present invention is applied, and in the figure, the right side is the front side of the laser beam printer 1. ing.

The laser beam printer 1 has a main body frame 2 and a printer front plate 5 whose base is pivotally connected by a hinge shaft 3 and can be opened and closed. The exterior main body 2 includes a process cartridge 6 as an image forming means. The process cartridge 6 includes a photosensitive drum 7 that rotates in the direction of the arrow, a developing device 9 that develops a latent image formed on the photosensitive drum 7, a cleaner, and the like. The laser beam scanner 10 irradiates the photosensitive tram 7 with a laser beam L corresponding to image information to form a latent image. The laser beam printer 1 has one paper feed cassette at the bottom of the main body frame 2, and the sheet material P2 stored in this cassette is transferred to a pair of registration rollers 1 by a feed roller 20.
After the toner image has been transferred to the photosensitive drum 7 and the toner image has been fixed by the fixing device 23, the sheet is discharged onto the paper discharge tray 26 by the discharge roller group 25.

The printer front plate 5 is provided with a detachable sheet material storage section 12, a feeding roller (sheet material feeding means) 15, a separation bat 13 in pressure contact therewith, and the like. As shown in FIG. 2, a feeding unit 27 including a sheet material storage section 12
Explain the details.

A drive shaft 16 on which a paper feed roller 15 is rotatably mounted.
An electromagnetic spring clutch 39 is arranged adjacent to the
The driving force of the drive shaft 16 is transmitted to the paper feed roller 15 by the operation of the electromagnetic spring 39. The drive shaft 16 is a bearing 3
A drive gear 37, which is rotatably supported by 5 and 36 and fixed to one end thereof, is rotated in the direction of arrow 29 by the transmission of driving force from the laser beam printer 1.

By connecting the switch 40a of the electric circuit 40 of the electromagnetic spring clutch 39, the electromagnetic spring clutch 39
The paper feed roller 15 connected to the output section is moved when the paper feed roller 15 is operated.

The sheet material P1 stacked in the sheet material storage section 12 is guided by the main body paper guide 41 and fed to the registration roller pair 17 as the paper feed roller 15 rotates. A sensor 42 provided during this feeding notifies the computer 11 shown in FIG. Complete feeding.

Next, a description will be given of how the intermediate plate 30 presses and releases the paper feed roller 15.

A cam row 45 is rotatably mounted on the drive shaft 16, and this cam row 45 includes an eccentric cam 45a shown in FIG.
The elongated biasing cam 45b shown in FIG. 6, the detection switch cam 45c shown in FIG. 5, and the notched gear 4 shown in FIG.
5d etc. are integrated. Drive shaft 1
The gear 46 fixed to the rotor 6 meshes with a long common gear 47, and the notched gear 45d can mesh with the common gear 47 when it rotates.

A pair of stoppers 45e are provided on one side of the notched gear 45d.
A pawl 51a at the free end of the clutch arm 51 engages with this stopper 45e, as shown in FIG. The clutch arm 51, whose base is pivotally supported by a support shaft 52, is moved by the claw 51 due to the elasticity of the bow tension spring 53.
a is biased in a direction that presses into contact with the notch gear 45d.

Further, the clutch arm 51 has a DC solenoid 5.
0 plunger 50a is pivotally mounted by a pin 50b.

A support arm 31 is fixed to the side of the middle plate 3o, and the protrusion 31a at the free end of the support arm 31 is supported by the eccentric cam 45a due to the elasticity of a tension spring 33 attached to the middle plate 30.
It is biased in the direction of pressure contact. Further, as shown in FIG. 6, one end of an arm 56 pivotally supported by a support shaft 55 is in pressure contact with the biasing cam 45b, and this arm 56 is moved in the direction of the arrow by a tension spring 57. It is biased in the direction of rotation. A biasing mechanism 59 is constituted by the biasing cam 45b, arm 56, tension spring 57, and the like. Further, a clutch mechanism 43 is constituted by a notched gear 45d, a clutch arm 51, a DC solenoid 5o, etc. shown in FIG.

The second
The switch 49a of the electric circuit 49 shown in the figure is operated, which causes the DC solenoid 50 to operate and the clutch arm 5
Remove the claw 51a of No. 1 from the stopper 45e of the notched gear 45d. Then, the arm 56 or the tension spring 5 shown in FIG.
7 rotates the biasing cam 45b in the direction of the arrow. At the same time, the notched gear 45d shown in FIG.
Rotate 1/2 turn in the direction of the arrow.

At this time, the power supply to the electric circuit 49 is stopped, and the Kra-Sochi arm 51 is in contact with the notched gear 45d due to the bow gravity of the bow tension spring 53. Since the notched gear 45d is provided with two stoppers 45e facing each other,
When the cam train 45 rotates 1/2, the stopper 45e again engages with the pawl 51a of the clutch arm 51, and the cam train 45 stops rotating. In addition, as shown in FIG. 4, the notched gear 45
When the common gear 47 is located in the notch d, a force is constantly applied to the cam train 45 to rotate in the direction of the arrow due to the action of the biasing mechanism 59 shown in FIG.

By this 1/2 rotation of the cam row 45, the state of the intermediate plate 30 changes from the position shown in FIG. 7 to the position shown in FIG. 8 as a result of the rotation of the eccentric cam 45a. That is, the eccentric cam 45a
or 1/2 turn from the position shown in Figure 7, the middle plate 3
0 rotates in the upward direction due to the elasticity of the tension spring 33, pressurizes the paper feed roller 15 against the sheet material P1 placed thereon, and thereby becomes ready for paper feeding. In this state, when the paper feed roller 15 is rotated, the sheet material P1 is continuously fed, and unlike the conventional device, the sheet material P1 is fed continuously.
There is no need to move the middle plate 3o up and down every time paper is fed.

By further performing the above operation and rotating the cam row 45 by 1/2, the relationship between the intermediate plate 30 and the paper feed roller 15 becomes the state shown in FIGS. 8 to 7, and the sheet material P1 is transferred to the paper feed roller 15. By being separated from the intermediate plate 30, it becomes possible to easily replenish the sheet material P1 to the intermediate plate 30.

In the series of pressurizing and releasing operations of the intermediate plate 30 against the paper feed roller 15 as described above, the intermediate plate 30 and the paper feed roller 15
The detection mechanism 6 shown in FIG.
3 is provided. This detection mechanism 63 is connected to the cam row 45
The switch arm 60 is in pressure contact with the cam 45C and rotates about a support shaft 61, and the switch board 62 has a switch 62a that is turned on and off by the switch arm 6°.

With the above configuration, the intermediate plate 30, that is, the sheet material P, is pressurized and released from the paper feed roller 15, and the sheet material P is fed by the paper feed roller 15 as a series of operations. In this embodiment, the clutch i mechanism for pressurizing and releasing the intermediate plate 30 is performed by the notched gear 45d, but it is also possible to use a latch mechanism as shown in FIG. 11.

Further, the clutch mechanism 43 including the cam row 45 mentioned above, the urging mechanism 59, etc. constitute a sheet material storage section driving means A, and this sheet material storage section driving means A is a separate unit that is connected to the sheet material feeding device. The main feeding unit 27 is assembled into the main feeding unit 27 to perform a series of feeding operations.

(g) As described in detail of the invention, the sheet material feeding device of the present invention has a sheet material feeding device such as a paper feeding roller and an electromagnetic spring clutch on a drive shaft that constantly rotates by receiving driving force from the main body. The following effects can be achieved by providing the sheet material storage section driving means for controlling the pressurization and release of the intermediate plate of the sheet material storage section.

(1) Sheet material exchange and replenishment can be set arbitrarily on the software, and there is no need to control the middle plate every time sheet material is fed, unlike conventional devices. In addition to improving durability, it is also possible to reduce impact noise when the intermediate plate is pressed against the sheet material feeding means.

(2) When feeding sheet materials, the rotation speed of the paper feed roller (sheet material feeding means) can be freely set according to the paper path, and the paper feed roller can be enlarged or rotated without being restricted by the outer diameter. Since the paper feed roller is directly driven by an electromagnetic spring clutch, hack tension during feeding can be reduced.

[Brief explanation of the drawing]

FIG. 1 is a vertical cross-sectional side view of a laser beam printer as an image forming apparatus to which the present invention is applied, FIG. 2 is a perspective view of a feeding unit, FIG. 3 is a plan view of a clutch mechanism, and FIG. Similarly, Fig. 5 is a front view, and Fig. 5 is a plan view of the detection mechanism.
The figure is a front view of the biasing m structure, Figures 7 and 8 are side views showing the pressurizing/releasing operation of the intermediate plate, and Figure 9 is an image formation using a conventional sheet material feeding device. FIG. 10 is a side view of the paper feed roller section, and FIGS. 11 and 12 are side views of the clutch mechanism section. Pl... Sheet material, 1... Laser beam printer (main unit W), 12... Sheet material storage section, 15
... Paper feed roller (sheet material feeding means) 39 ... Electromagnetic spring clutch (driving means) 45 ... Cam row, 4
3...clutch mechanism 59...biasing mechanism, 63.
...Detection mechanism A...Sheet material storage section driving means Fig. 3

Claims (1)

[Claims] 1. Feeding the sheet materials stored in the sheet material storage section one by one to a main unit that receives the sheet materials and executes a predetermined process of forming an image on the sheet materials. A sheet material feeding device comprising: a sheet material feeding means for feeding the sheet material in the sheet material storage section; and a drive transmission means for driving the sheet material feeding means. sending device. 2. The sheet according to claim 1, wherein the sheet material storage section includes a sheet material storage section driving means that pressurizes and releases the sheet material from the feeding means, together with the feeding means and the drive transmission means. Material feeding device.